U.S. Pat. No. 7,042,440, which issued to Pryor, et al., on May 9, 2006, discloses methods and apparatus for inputting position, attitude (orientation) or other object characteristic data to computers for the purpose of Computer Aided Design, Painting, Medicine, Teaching, Gaming, Toys, Simulations, Aids to the disabled, and internet or other experiences.
U.S. Pat. No. 7,053,915, which issued to Jung, et al., on May 30, 2006, discloses a system and method for increasing the value of the audio-visual entertainment systems, such as karaoke, by simulating a virtual stage environment and enhancing the user's facial image in a continuous video input, automatically, dynamically and in real-time.